Artificial tooth.



G. EVANS.

ARTIFICIAL 100m.

Patent-ed (m. 16, 1917.

INVENTOR a QO'LOKS I By A izorneys,

GW.&MAL%

GEQRGE EVANS, OF NEW YORK, .Ll'. Y.

ARTIFICIAL TOOTH.

Application filed October 18, 1916.

To all whom it may concern:

Be it known that T, GEORGE Evans, a citizen or the United States of America, residing in the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Artificial Teeth, of which the following is a specification.

This invention relates to artificial teeth designed chiefly for use in bridge work. in restoring lost teeth in the bridge system, the vacant space is filled with an artificial tooth, or teeth, supported by a bridge structure having its abutments on the adjoining natural teeth or roots. At present such artificial teeth are commonly made of gold, or partly of gold and partly of porcelain; the gold portion being united by soldering to the gold of the abutment, crown, or attachment. Commonly, the front or chief visible portion of the tooth is of porcelain, the bcclusal or grinding face is of gold, and more or less of the back of the tooth is of gold, the porcelain portion being formed with pins baked in the porcelain and projecting into the gold portion to firmly atta'ch the tooth. in other cases, the tooth is made entirely of porcelain, its base or cervical portion being diminished suficiently to provide room for a gold base, or bridge, and the porcelain tooth has a hole extending from the cervical portion into or entirely through it to receive a pin projecting from the gold base for fastening the porcelain tooth thereto, the pin losing cemented into the hole.

The present invention reverses the ordi nary procedure in that the porcelain tooth has the hole for attachment to the pin projecting from the gold base, or bridge, entering it from its occlusal portion and passing only partly through it so that its cervical portion is imperforate. Preferably, also, more or less of the occlusal portion oi the tooth is wanting in the porcelain, being supplied by the gold bridge. It results that the wearing face of a bridge tooth, or teeth, is of gold and constitutes the bridge or support, the remainder of the tooth being of porcelain and being, as it were, suspended from the bridge.

The construction will be made more clear with reference to the accompanying draw- Specification of Letters Patent.

Patented Get. 16, 191?.

Serial No. 126,340.

ings, showing suitable embodiments of the invention.

Figure l is an elevation, partly in section, showing the gold bridge with its abutinents and two teeth intervening the abutments, one being in place and the other displaced for better illustration;

Fig. 2 is a transverse section through one of the artificial teeth.

Fig. 3 is a diagrammatic view of a tooth;

Figs. 4 and 5 are sectional views showing two other forms of porcelain teeth made according to this invention;

Fig. 6 is a section showing a flange on the bridge partly embracing the porcelain tooth.

In Fig. 1 A, A are the butments; B is the bridge, and C, C are the porcelain teeth. The abutments A, A may be natural teeth, or may be gold caps applied on natural roots. The bridge B is'of gold and forms the occlusal portion of the missing teeth. The bridge has pins D, D projecting from it (downwardly in the figure). The porcelain teeth C, C have holes E, E for admitting these pins, these holes entering from the occlusal end of the porcelain teeth and projecting toward, but not through, the cervical face. Cement being inserted in these holes, the porcelain teeth are thereby cemented to the pins.

Referring to Fig. 3, the tooth is shown as divided into three equal parts, namely: the occlusal third at, the middle section a and the cervical third 0. The occlusal third may be formed more or less of the gold portion B constituting the bridge. This portion should be only thick enough to give the required strength in order to have as little gold visible as possible. In the forms shown in Figs. 4 and 5, the occlusal portion is complete in the porcelain tooth, as a natural tooth. The cervical portion may be convexly rounded, as shown in Fi 4, or may be somewhat reduced to con orm to the shape of the gum, as shown at F in Figs. 3 and 5. Fig. 2 showsthe relation of the gum G to the reduced portion F.

The object of the use of porcelain in preference to gold is, that the surface of gold is oxidized by secretions of the mouth, that deposits of or from the food more readily adhere and collect on its surface than porcelain so that it is more dificult to keep clean,

interrupted surface ei the never become changed, is cleansed, and consequently is more benign in its presence to gum tissue.

The smooth and rounded shape of the porcelain is also more agreeable to the tongue than the curved or V-ShfiPQFl one heretofore generally used.

In attaching the porcelain tooth to the metal bridge or support, the ordinary dental cement may be used, or, for work of a superior grade, the bridge may be made of suitable refractory metal and the porcelain tooth may be fused to the bridge by the use of a low-fusing porcelain as a cement instead of using the ordinary dental cement. In such case the bridge should be made of a platinum gold alloy, which should contain at least twenty-five per cent. (25%) platinum and may contain as much as thirtyfive per cent. (85%) platinum to advantage; such an alloy is so refractory as to readily withstand the heat necessary for fusing such low-fusing porcelain as is adaptable to the cementing of the porcelain tooth to the metal bridge. Or it is practicable to make the body of the bridge of platinized gold (being gold containing one per cent. or upward of platinum) and the union of the sections of the bridge with the porcelain teeth of pure gold, using a low-fusing porcelain, such as Jenkins porcelain, for cementing the porcelain teeth to the bridge by fusion.

In the case of great absorption of the gum under the artificial tooth, on teeth, the lat" ter may be removed from the gold bridge and replaced with longer artificial teeth. In some cases this may be done without removing the bridge from the mouth. The construction also -.tacilitatee repair in Y the bra kageot a porcelain teeth, due to the manner of attachment and constitutes an important advantage.

The invention is susceptible to those ficaticns which will be obvious te workers in the dental art. F or example, While the tachment of the porcelain tooth to the metal support by pins on the latter entering the holes or sockets in the former is the preferable means, yet other attaching means may be substituted, such as the construction of the bridge or metal support with a flange or capembracing the occlusal end of the porcelain tooth, whereby the latter is supported or suspended from the bridge without the requirement of pins.

Such an attachment is shown in Fig. 6, the flange being lettered d, it being understood that the pin D may be omitted.

I claim as my invention 1. An artificial tooth having a hole extending from the occlusal surface toward but not through the cervical portion.

2. An artificial denture comprising a metal bridge forming the occlusal surface and having a projecting pin, and a suspended tooth of porcelain having a hole receiving said pin, extending toward, but not through the cervical portion.

3. An artificial denture comprisin a metal bridge forming the occlusal surr'ace, and a suspended toot-h of porcelain united to the bridge on its occlusal end.

In witness whereof, I have hereunto signed my name in the presence of a sub scribing witness.

GEURGE EVANS. Witness:

CHAs. lZroN RUSSELL. 

